No email other than gmail.
Running OpenOffice rather than MS Office (but Viruses aren't the reason I'm using OO, and neither is a dislike for MS).
Hardware firewall + whatever XP's firewall adds.
Opera.
I don't click IM links unless I'm expecting one, and I use Trillian.
Maybe some others I can't think of right now.

Depends on which computer. I have 2 Apple computers, 2 Windows boxes (one I rarely physically touch, media center), and 1 linux box. In reality I use linux the least, likely because its only single monitor setup

I'm one of the two people who said "I don't use Antivirus." I don't use it because A) I've never got a virus in my life (only spyware). B) I reformat my HDD(s) every 4 months. And C) I never have anything valuable stored on my HDD. That's all on my removable USB drive that's never plugged into my system except for while I'm copying things to it.

I would use it if it didn't complicate the process of playing online games, and if it didn't slow my boot times and have a small impact on game performance (depends on the brand I guess though).

Since I reformat every 4 months, I don't really care if I get a virus because I'm so used to reformatting that it barely bothers me if I have to do it 2 times in a week.